Burner for the autogenous cutting of metals



July 3, 1921?.v 1,460,662

A. B. DRGER ETAL BURNER FOR THE AUTOGENOUS CUTTING OF METALS Filed Aug. 18. 1921 2 Sheets-Sheet 1 Julys, 1923. 1,460,662

, A. B. DRAGER ET AL BURNER FOR THE AUTOGENOUS CUTTING OF METALS Filed All- `18, 1921 2 Sheets-Sheet 42 VEN ORS C?! mdf/u mu/Mdm www Patented July 3, 1923.

iJ'rEDv STATE ALEXANDER BERNHARD DRAG-ER, HANS WILHELM CHRISTIAN SCHRDER, AND ERNST WILHELM KUNZMANN, Oil? LBECK, GERMANY; SAID SCHRDER AND SAID XUNZMANN ASSIGNORS TO SAID DRGER. V

BURNER FOR THE AUTOGENOUSYCUTTING 0F METALS.'

Applicationled August 18, 1921.

Toallwhomz'tmay comem:

Be it known that we, ALEXANDER BEEN- HARD DRGER, HANS WILHELM CHRISTIAN SCHRDER, and Ems'r WILHELM KUNz- MANN, German citizens, residing at Lubeck Germany, have invented certain new and useful Improvements in Burners for the Autogenous Cutting of Metals (for which we have tiled applications in Germany, June 2, 1920, and June 19, 1920), of which the following is a specification.

The present invention relates to burners for the autogenous cutting of metals.

In hitherto known burners with a central oxygen cutting-jet and an annular concentric space for a heating flame, the inner oxygen cutting-nozzle is screwed into the oxygen supply bore of the burner head, and the outer heating nozzle is likewise screwed into the burner head and forms around the inner nozzle the annular passage for the heating gas. that in this `arrangement, in consequence of unavoidable errors in manufacture in all the parts, and` frequently through wear, no exactly concentric position of the nozzles, and consequently no uniform annular outlet opening or slit for the heating ame, can be obtained. The heating flame must however, in order to produce a good cut all around and not Hash back into the burner at the slightest resistance, always issue from an annular passage of perfectly uniform width and concentricity. 4

According to this invention this requirement is complied with by the special method of construction of the nozzles. The small errors in manufacture are no longer capable of influencing the concentric position of the nozzles, and any wearing of the nozzles and burner heads is not detrimental to the correct action of the burner.

The packing 0f a nozzle with two separate bores as gas conduits also o'ers considerable diiculty. Only when this question is satisfactorily solved can such a nozzle arrangement Y be used at all. Before all things it must be taken into consideration that a large number of nozzles must fit one burner head. The fitting of such nozzles to the burner head by grinding and the like is therefore impossible. Furthermore packing rings of the usual materials, such as vulucamzed fibre, pasteboard, leather, rub- It has however been foundv serial No. 493,413.

ber and the like, cannot be used, as the heating thereof has to bereckoned with.

According to this invention aneiicient packing is secured between the body of the nozzle and the separate supply pipes for the oxygen and the heating gas in the body of the burner, by the aid of two concentric crater or tapered packing rings, which are provided either onthe inner end face of the nozzle and act as a packing against a surf-ace turnedl fiat at the base of the recess turned in the head of the burner, or conversely, are provided at the base of the recess turned in the head of the burner and .ing chamber and annular outlet slit for the heating gas situ-ated between the oxygen nozzle with its outlet union, and the cap of the mouthpiece or heating jet, the apparatus being so constructed that these two' chambers through which the mixed gas.

passes are of the same, or approximately the same, cross sectional area over the whole of the course traversed by the gas, and that the length of the annular passage is definitely roportional tothe veloclty of the ow ofP the gas and to the retrograde absorption of heat by the nozzles, in order to still more efliciently prevent the striking back of -the heating liame in the burner.

Finally, according to this invention, that part which, in ordinary use of the burner, is next the cap of the mouthpiece and is mostly subjected to wear or destruction through careless handling, that is the outlet tip of the oxygen nozzle, can be made as a separate part and inserted linterchangeably 'and gas tightI in the oxygen nozzle. -In case of any damage, which only extends to this outlet tip, this latter \then only needs to be interchanged.

Several constructional examples of the inthe accompanying through a burner head of somewhat differentc constructional form as regards the packing' l p g supplies the heating gas.

between the oxygen or cutting nozzle and` through a burner head of somewhat different constructional form.

Figure 7 shows likewise in longitudinal section a burner head, in which however the outlet tip of the oxygen nozzle is interchangeable, the heating nozzle being screwed on to an external screw thread on the oxygen nozzle.

with an interchangeable outlet nozzle, in

which however the preliminary heatinO' nozzle is screwed into an internal screw thread in the oxygen nozzle.

Similar letters of reference refer to similar parts throughout the several figures.

From the burner handle a, lead two pipes b and a (Figure 1) constituting respectively oxygen and heating gas supply pipes to the burner head d which is provided with an inner nozzle e and aniouter nozzle-cap or mouth-piece h. The concentric bore f (see Figures 2 and 3) of the burner head d supplies the oxygen, and the eccentric bore In the inner nozzle e are provided separate bores or passages, the central one z' being .for the oxygen and the others 7c which surround it, for the heating gas. The lower or end portion of the nozzle e is shouldered to form a projecting central nozzle-tip Z traversed by a concentric bore which is coaxial and communicates with the oxygen passage z'. This nozzle-tip Z forms the oxygen outlet proper. The shouldered end portion of the nozzle e is provided with an external screw thread, on to which is' screwed the nozzle-cap It which 1*has a central opening or hole in it which is slipped over the nozzle-tip Z. In its inal position this cap or mouth piece is spaced from the nozzle e to provide a chamber m in which the heating gas is collected and from which it is conveyed, and to convey it into the annular slit between the nozzle-tip Z and the wall of the' central opening in the cap, the diameter of which opening is obviously slightly greater than that of the nozzle-tip Z. It will be readily seen that with this arrangement the centering of the nozzle and nozzle-tip e, Z and the cap ZL is eifected in a simple. and efficient manner. For accurate adjustment it is only necessary that the nozzle-tip Z and the central ineoea opening of the `cap L be coaxial with the screw-joint between the cap h and the nozzle-body e, that is to say, with the female and male threads of this screw-joint.

Formerly in the hitherto known burners the socket of a separate inner nozzle and the opening of an outer nozzle had to run coaxially with two screw-joints, one connecting the inner nozzle and the other the outer nozzle with the nozzle-body.

As the nozzle and nozzle-tip e, Z and the capk are not separated from each other when once screwed up, but are interchanged as a whole, no wear of the threads and the surfaces takes place, which effect the centering. Permanently uniformly working nozzles aretherefore obtained and much time is saved when interchanging the nozzles for cutting work-pieces of dlierent thicknesses.

vThe methods of packing shown in Figures P. 2 and 3 have proved to be suitable for the Figure 8 shows a similar burner head yIn order to .protect 'the tapered rings when the nozzle e is unscrewed, aprotecting ledge or border p is provided outside the outer ring o. The second method of packing which can as well be used, is shown in Figure 3. In this case, only one tapered ring n is used to pack the oxygen conduit, while the packing for the heatingl gas, which is under low pressure, is formed by an asbestos packing ring g and a gland-nut 1'. The packing ring g is pressed by the nut '1' against the burner head il and against the external screw-thread of the nozzle e.

The present invention renders the manipulation of the new burner considerably more simple in comparison with the known burners with two interchangeable nozzles. Furthermore the nozzles cannot be wrongly interchanged with each other as in the case of well known burners with two interchangeable nozzles, which when used the wrong way round may under some circumstances result in an accumulation of the heating gas and in the case of using a gas consisting of a mixture of oxygen and a heating gas, a passing back of the oxygen into the heating gas conduit. The principal l advantage of this invention is however that the centering of the nozzles is easily obtained and ensured, and is not subjected to any change.

In the constructional form shown in Fig-' ure 4 the tapered rings n1 'o1 are mounted on the burner head d, while the fiat surface e2 is provided on the nozzle e1. It is however necessary and also usual, for the burner head, which carries the tapered rings, to consist of a hard metal and the nozzle of a softer metal such as copper for example. By this means it is ensured that the form of the tapered packing rings is maintained, while they become pressed into the soft material of the nozzle when the latter is screwed in and tightened up. An absolutely satisfactory packin between metal and metal is rendered particularly possible by sli htly deforming one of the two packing sur aces. The inner ring nl, which is of a smaller diameter, can force itself more easily into the mouthpiece el when the latter is tightened up than the external ring o1 of larger diameter. In consequence thereof it is convenient to make the inner ring nl project slightly beyond the outer ring o1 and therefore touch the mouthpiece first when screwed in. (This arrangement ofthe rings is shown in Figure 4). The inner ring nl, after'the nozzle e1 has been completely tightened up, will provide a larger packing surface at the nozzle than the outer ring 01, which is advantageous because the central oxygen is under a higher pressure than the heating gas.

It is of special advanta e in the manufacture of the apparatus t at the tapered packing rings are contained in the burner and that the mouthpiece is provided with a iat surface e2, as the production and testing of an accurate external flat surface offers no diiculty. The case is however diE'erent when the arrangement of Hat surface and pointed rings is reversed. The latter are also better protected against damage when situated in the head ofthe burner than they are when provided on the mouthiece.

p Should any damage happen to the at surface e2 of the mouthpiece, this surface can be ound down on a flat emerywheel or the like and thereby again made lit for use.

It will be easily seen that a simultaneous packing of several passages in the manner described is attained in a more perfect manner taking into consideration the usual material, the ease of production, the interchangeability and the upkeep. A reliable packing between the headof the burner and the mouthpiece is however an absolute necessity for the proper and safe working of the burner.

When using 'mixed gas as the heating gas, the disadvantage has been experienced, that when the burner becomes highly heated after cutting periods of long duration or when showers of sparks are produced, .or when low externalgresistance occurs in the burner, the heating llame strikes back to the mixing point and destroys the internal parts.

According to the present invention this disadvantage can be obviated by the special construction lof the collecting chamber m (see Figures l and 2) and of the annular outlet slit between the nozzle-tip Z of the nozzle and the cap or mouthpiece h. Fi ures 5 and 6 show two constructional examples of burners with such improved passages for the passa e of the mixed gas. The nozzle e, h may 1n this case be screwed into the head d of the burner separately, as is shown in Figure 5, or the outer nozzle L can be screwed as a cap on to the inner nozzle e (see Figure 6). In both constructional forms a collecting chamber m1 for the mixed gas and an annular outlet passage kl is formed in the front part between both nozzles.

ln the known burners, which are not so constructed the mixed gas dame burns quietly in front of the annular passage as long as the speed at which it issues is so high and the temperature of the issuing mixed gas is so low that the burner zone forms'an outwardly directed conical ring. When however owing to uncertain guiding of the burner, fused metal, or an excess of pressure produced by the cutting oxygen a resistance is formed in front of the nozzles, or when excessive heating of the nozzles takes place owing to reflex radiation particularly when piercing holes, the burner zone runs back into the annular passage. Striking back also takes place by the action of flying sparks which get into the annular passage. It is then said that the speed of i ition exceeds the speed of .issue or flow. Ifgn fore the conditions .are favourable to the flame to continue burning in the burner in such a way that the path of the supply of the mixed gases becomes reduced from a wider cross sectional area to a.narrower one by degrees up to the point of issue, Vor immediately in front of it, that is to say the speed of ow decreases in aback-ward direction, the flame runs back to the mixing point of the gases and can then only be put out by shutting oil' the valves. On the lbasis of this knowledge therefore the amnulalr passage h1 and the adjoining collecting chamber m1 are soA constructed in the subject matter of the invention, that the speed of flow'is sucient at this point to prevent therethe running back of the flame into thewider Asupply passages c-or k1 (or the groovesI) in t is able effect, -upon the kinetic energy of How..

This xed minimum is in relationship to the speed of flow, or the proportion between the volume of flow and cross sectional area.

A similar dependence exists between the length of the annular passa/ge and the degrec of heating which the nozzles are subjected in the treatment of pieces of work. The points of the nozzles become very hot but farther backwards the tempera-ture is kept down bythe gas as it flows in. llt is therefore important to allow the high speed tend only into the front part of the annular passage and immediately after the cessation of the cause, which' only arises temporarily, the flame again burns normally in front of the nozzles without being capable of damaging them in any way whatsoever.

The novelty of the constructional examples shown in Figures 7 and 8 consist in making the oxygen or cutting nozzle in two parts, namely the nozzle part e separated from the pipe f (oxygen) and g (heating or combustible gas) in the burner head d by tapered packing rings n and o and the nozzle-tip Z1 or Z2. This latter` can be inserted gas tight in the part e by being screwed in, forced in or in any other suitable manner, so that in\case of necessity it can be easily interchanged.` This interchangeability of the nozzle-tip Z1 or Z2 con stitutes the great advantage compared with the oxygen nozzles with fixed sockets (see Figures 2, y3 and 5, 6).

The centering of the parts e and Z or Z2, once carried out when replacing or repairing them for the purpose of providing an accurate annular opening between the part e. and the cap it, remains constant during the use of the burner as it is always only the mouthpiece, consisting of the parts e, Z1, 7L

or e, Z2, h, which is interchanged as a whole for cutting the different thicknesses of material.

lt is ,universally known that the emouthpieces of burners which are subjected to the actionrof showers of sparks and the striking back of the heating flame must be made oi copper. The construction of the mouthpiece in three parts according to Figures 7 and 8, therefore o'ers in comparison with the construction thereoi` in twoy parts according to Figures 2, 3, 5 and 6 the improvement that the screw portion e which is less subjected to the action of the ame, can be made of a metal which is cheaper, harder and easier to work, such for example as brass. The increased hardness means greater durability against the mechanical strain produced by the Spanner when interchanging the mouthpieces.

Between the constructional forms according to Figures 7 and 8 there are only differences of an economical kind.

In the first case according to Figure 7 a smaller nozzle-tip Z1' is necessary, but an increased amount of work when boring the longer screw ortion e. In the second case according to igure- 8 the contrary is the case, i. e. a larger nozzle-tip Z2 and shorter screw portion e.

We claim:

1. In a burner for the autogenous cutting of metals with a central oxygen cutting jet and an annular concentric heating ame, the combination of a burner head, a nozzle detachably connected. therewith and pro- 'vided with a concentrlc oxygen passage and a passage for a heating gas, means on said nozzle co-operating with said head to provide a packing whereby said oxygen and gas passages are sealed against communication with each other at this point, a nozzle-tip carried by said nozzle and constituting an outlet for the oxygen and a nozzle-cap carried by said nozzle and forming therewith a gas collecting chamber communicating with said gas passage, said nozzle-cap being provided with a central opening through which said nozzle-tip projects and of larger diameter than said nozzle-ti to form therewith an annular outlet slit ihr said heating as. g 2. In a burner for the autogenous cutting of metals with a central oxygen cutting jet and an annular concentric heating flame, the combination of a burner head, a nozzle detachably connected therewith and provided with a concentric oxygen passage and' .a passage for a heating gas, concentrictapering rings located between said burner head and nozzle and comprising an integral part of one of said elements in engagement with the other of said elements to providea p-acking whereby said oxygen and gas passages are sealed against communication with each other at `this point, a nozzle-tip carried by said nozzle and constituting an outlet for the oxygen and a nozzle-cap carried by said nozzle and forming therewith a gas collecting chamber communicating with said gas passage, said nozzle-cap being provided with a central `opening through which said nozzle-tip projects and of larger diameter than said nozzle-tip to form therewith, an annular outlet slit for said heating gas.

3. In a burner for the autogenous cutting of metals with a central oxygen cutting jet and an annular concentric heating name,

the combination of a burner head, a nozzle detachably connected therewith and provided with a concentric oxygen passage and a passage for. a heating gas, said nozzle having a flat inner end surface, concentric tapering rings comprisingan integral part of said burner head and engaging said flat surface of the nozzle to comprise a packing whereby said oxygen and gas passages are sealed against communication with each other at this point, a nozzle-tip carried by said nozzle and constituting an outlet for the oxygen and a nozzle-cap carried by said nozzle and forming therewith a gas collecting chamber communicating with said` gas passage, said nozzle-cap being provided with a central'opening through which said nozzletip projects and of larger .diameter than said nozzle-tip to form therewith an annular outlet slit for said'heating gas.

4. In a burner for the autogenous cutting of metals with a central oxygen cutting jet and an annular concentric heating flame,

the combination of a 'burner head, a nozzle detachably connected therewith and provided with a concentric oxygen passage and a passage for a heating gas, said nozzle having a flat inner end surface, concentric tapering rings comprising an integral part of said burner head and vengaging said flat surface of the nozzle to comprlse a packing whereby said oxygen and gas passagesare sealed against communicationwith each otherl at this -point,'said inner ring projecting slightly beyond the outer ringandengaging said endsurface in advance of theouter ring as the parts are assembled, a nozzle-tip carrled by said nozzle and con- :stituting an outlet for the oxygen and a nozzle-cap carried by said nozzle and forming therewith a gas collecting chamber com,- municating with said gas passage, said nozzle-cap being provided with a centralopening through which said nozzle-tip pro]ects and of larger diameter than said nozzle-tip to form therewith an annular outlet slit for said heating gas. y

' 5. In a burner for the autogenous cutting of metals with a central oxygn cutting jet and an annular concentric eating llame,

the combination of a burner head, a'nozzle detachably connected therewith and provided wit a concentric oxygen passage and which said nozzle-tip projects and of larger diameter than said nozzle-tip to form therewith an annular outlet slit forsaid heating gas, saidcollectingY chamber and outlet slit for the heating gas being of approximately the same cross-sectional .area over the whole of the path traversed b y the gas and the length of the annular sit for the purpose of preventing the striking back of the preliminary heating flame into the burner.

6. In a burner for the autogenous cutting of metals with a central oxygen cutting jet and an annular concentric heating flame, the combination of a burner head, a nozzle detachably connected therewith and provided with a concentric oxygen passage and a passage for a heating gas, means on said nozzle co-operating with said head Ito provide a packing whereby said oxygen and gas passages are sealed against communication with each other at this point, a nozzle-tip comprsing a separate element -detachably connected with said nozzle and constituting an outlet for the oxygen and a nozzle-cap carried by said nozzle and forming therewith a glas collecting chamber communicating wit ysaid gas passage, saidnozzle-cap being provided with a central openin through which said nozzle-tip projects an lof larger diameter than said nozzle-tip to form therebeing deiinitely i proportioned to the speed fof low and the 'reflex absorption of the heat by the nozzles with an annular. outlet slit for said heating gas.

Witnesses:

FELIX SOHWEIOHLER, ERNEST H. L.`MUMMENH0FF. 

